Cut-out geometrical figure for didactical purposes.



M. MONTESSORL CUT-OUT GEOMETRICAL FIGURE FOR DIDACTICAL PURPOSES.

APPLICATION FILED MAR. 18, I9l3.

Patented Feb. 29, 1916.

Fig.7

Fwd.

V T T A THE COLUMBIA PLANOGRAPH co., WASHINGTON, D. c.

'venience in handling the insets IMARIA MONTESSORI, OF HOME, ITALY.

Application filed March 18, 1913.

To all whom it may concern:

Be it known that I, MARIA Monrnssonr, a subject of the King of Italy,residing at Rome, Italy, (whose post-otfice address is 1 Via PrincipessaClotilde, doctor of medicine, have invented certain new and usefulImprovements in Cut-Out Geometrical F igures for Didactical Purposes, ofwhich the following is a specification.

This invention relates to an improvement in educational devices and moreparticularly to a device by means of which fundamental principles ofgeometry may be easily and rapidly taught to young pupils.

The invention broadly consists of a plate or the like provided with aplurality of recesses of geometrical shapes and a plurality of insetsadapted to be placed within each of the recesses to exactly fill thesame.

In the accompanying drawing illustrating the invention, Figure 1 shows aplate provided with two recesses of equilateral triangular formation andinsets adapted to fill the recesses; Fig. 2 shows a plate similar tothat shown in Fig. 1, the insets being of a different shape than thoseshown in Fig. 1; Figs. 3, l and 5 each show a plate provided withrecesses of different shapes and insets adapted to fill each of therecesse Referring to 1, a represents a plate of any suitable materialand provided with two similar recesses of equilateral triangularformation. The term recess as used herein is intended to include anymechanism which will form a permanent record of the relations betweenthe respective geometric shapes and be provided with boundaries tocontain the insets when properly grouped. Insets b are provided whichare similar to one another in all respects and which are in the shape ofscalene triangles. The areas and shapes of the insets b are such thattwo of them placed in the position shown in the figure will exactly fillone of the equilateral triangular recesses in the plate a. For conb theyare provided with knobs or handles 0.

Referring to Fig. 2, the plate a is the same as the plate shown in Fig.1 but the number and form of the insets are different. As shown in Fig.2 there are four insets b of equilateral triangular shape which may begrouped to exactly fill either one of the recesses in the plate a.Inasmuch as the recesses in the plate shown in Fig. 2 are theSpecification of Letters Patent.

GUT-OUT GEOMETRICAII FIGURE FOR DIIDAGTICAL PURPOSES.

Patented Feb. 29, 1916.

Serial No. 755,148.

same shape and size as the recesses in the plate shown in Fig. 1 it willbe evident to the pupil that the area of the two scalene triangularinsets is equal to the area of the four equilateral triangular insets.

Referring to Fig. 3, the plate a is provided with a triangular recessand a rectangular recess, the longer side of which is equal to the baseof the triangle and the shorter side of which is equal to one half thealtitude of the triangle. A set of three insets is provided which are ofsuch shape and size that by grouping them in one way they will entirelyfill the triangularecess and by grouping them in a different way theywill entirely fill the rectangular recess, thus teaching the pupil thatthe area of a triangle is equal to the area of a rectangle having thesame base and one half the altitude of the triangle.

In Fig. 4 of the drawing the plate a is provided with a recess havingthe shape of a trapezoid and a second area of rectangular shape, thelonger side of which is equal to the sum of the length of the two basesof the trapezoid and the shorter side of which is equal to one half thealtitude of the trapezoid. A set of four insets is provided which are ofsuch shapes that they may be arranged in one way to completely fill thetrapezoidal recess or they may be arranged in a different way tocompletely fill the rectangular recess, thus indicating to the pupilthat the areas of the two recesses are the same.

In a like manner the form of the apparatus shown in Fig. 5 illustratesthe similarity in areas of a rhombus and a square.

It will of course be understood that the shapes and sizes of therecesses in the plate and the number and shapes and sizes of the insetsmay be varied from those shown in the drawing without in any waydeparting from the spirit of the invention.

Having described this invention in con nection with the illustrativeembodiments thereof, to the details of which disclosure the invention isnot, of course, to be limited, what is claimed as new and and what isdesired to be secured by Letters Patent is set forth in the appendedclaims:

1. In an educational device, in combination, a plate provided with aplurality of geometrically related cavities of different shapes and aplurality of insets adapted to be grouped together to fill exactly anyone of said related cavities.

2. In an educational device, in combination, a plate provided with aplurality of geometrically related cavities of different shapes ofgeometrical form and a plurality of insets adapted to be groupedtogether to fill exactly any one of said related cavities.

In an educational device, in combination, a plate provided with aplurality of cavities of different shapes but of the same area and aplurality of insets adapted to be grouped together in different Ways tofill exactly any one of said plurality of cavities.

4. In an educational device, in combination, a plate provided With aplurality of geometrically related cavities of difierent shapes anda'plurality of insets adapted to be grouped together to fill exactly anyone of said related cavities, each of said insets being provided with ahandle.

5. In an educational device, in combination, a plate provided with aplurality of recesses of different shapes, said recesses beinggeometrically related in both volume each of said recesses having closedbottom and sides and an open top, said recesses be ing geometricallyrelated in both volume and area, and a plurality of fillers adapted byappropriately shifting the component parts thereof with respect to eachother, to

fit exactly any one of said recesses.

In'testimony whereof I have aiiixed my signature. Y 7

MARIA MONTESSORI.

01 this Patent may be obtained for five cents each, lay-addressing the(Commissioner of -1?atents,

Washington, -D. G. v

